1. Field of the Invention
The present invention relates to power plant equipment overheating and fire detection methods and systems. Exemplary power plant equipment includes generators, steam or gas turbines and power distribution and control apparatus including circuit protection, energy storage capacitor banks, power conditioning equipment, and the like. More particularly, the present invention utilizes plural types of equipment overheating monitoring detectors, such as smoke detectors and temperature detectors, that are sampled in parallel in real time. The system determines in real time a likelihood of whether any of the types of detector samples, alone or in combination with other types of detector samples, is indicative of monitored equipment overheating. An exemplary determination is made by referencing previously stored information that associates respective types of detector sample reading levels, or combinations of respective types of detector sample reading levels, with equipment overheating, and establishing an overall overheating determination confidence level. If the overall overheating determination confidence level exceeds certain levels, then different actions can be implemented based on the confidence level. For instance, a confidence level of 1% might result in an operator information only warning. A confidence level of 40% might result in a high priority warning accompanied by beeper, text, annunciation or automatic email alerting. A confidence of 80% might result in alarms and automatic fire control activation.
2. Description of the Prior Art
Existing power plant equipment overheating and fire detection systems often utilize a single type of detector technology that tends to be more effective at detecting a specialized group of events than a broad spectrum of all potential events. In view of this operational challenge, any particular type of detector may be relatively ineffective for some types of events if it has a tendency to issue false alarms where there is no actual overheating or fire condition. For example, optical smoke detectors detect smoke that is visible within the detector's emission light frequency. Smoke that is not visible within the detector's frequency spectrum alarm will not be detected. Conversely atmospheric water vapor in high humidity environments may trigger false alarms.
Another detector system operational challenge is binary operation or alarming: for example, the detector only alarms under one condition and is otherwise silent; the detector activates a sprinkler system or otherwise does not; the detector has a single output reading (e.g., “alarm” or silent). Thus, conventional detector systems rely on human intuitive judgment to determine whether a true overheating incident is occurring or whether it is merely a false alarm. A rigid, rules base detection system relying on a single digital alarm/no alarm information input is very impractical unless the triggering event is sufficiently grave to warrant conservative automatic alarm decision making and subsequent action. For example, a sprinkler system fire detector may require detected temperature to be sufficiently high to allow power plant equipment to be damaged by overheating rather than risk shutting down the plant or spraying water on equipment. In the case of a halide fire suppression system one would not want automatic suppression triggering if human operators are present in the suppression volume.
A human-monitored power plant overheating detection system allows an experienced operator to evaluate a detector alarm in the context of historical plant operation and other available information so that an ultimate conclusion of whether an overheating or fire condition is likely to exist is based at least on an intuitive probability analysis of plural information sources. For example, based on past operational history it may be known that a specific generator emits smoke under certain load conditions that is not considered harmful to the power plant. In another exemplary scenario, welding or other repair activities may generate smoke that is sensed by a smoke detector, but the operator knows that the smoke is not attributed to the monitored generator operation.
Thus, a need exists in the art for a power plant overheating detection system that can in real time monitor plural types of detector inputs, evaluate whether the inputs separately or in combination are indicative of an overheating condition by referencing stored information resources, and, as is performed by a human operator, make an overall confidence level determination of whether the monitored power plant equipment is experiencing an overheating condition.